loeryder21

i helped my friend install a cobra upper and lower set on an 86 gt and its running horrible. Would it be possible that the vaccuum lines are wrong which is causing this? we never got a diagram or anything so we werent sure which lines went where, just kinda did it randomly. I cant find too much online so i figured i would give you experts a shout out
Thanks

a_penquin

quite possibly a mixed vacuum line, maybe a vacuum leak could be a culprit. would get a diagram for the line locations first then work from there

nacanitihs

hose it down with some carb cleaner to see if there is a leak. if so the rpm will rise. its also kinda hard to mess up the vac lines as they all go to basically the same point.. and there is only like 3 that you touch doing an intake

loeryder21

any idea where i could get one? i think it might be on the tree under the intake where i messed up but im not sure, is there a site or anything?

AdderMk2

make sure you dont have a vac line directly to the EGR

nacanitihs

http://www.veryuseful.com/mustang/te...g5.0Vacuum.gif
i know it says 88 but it would be the same

here is the rest of the links in case you need any more
http://www.veryuseful.com/mustang/tech/engine/#Diagrams


are you sure you installed the lower correctly? did you use the noodle or cork?

loeryder21

thanks for the diagram, what do you mean noodle or cork? im pretty sure i installed it right... didnt seem too complicated.

nacanitihs

on the lower. the front and rear part of the gaskets. was it blue and rubbery or was it made of cork? did you use a little rtv on the corners or a lot? too much can cause a leak and so can too little.. u need just the right amount. but spray the intake where the gaskets are w/ carb cleaner to see if the rpm rises like i said earlier

also if you dont place the lower just right the gaskets can move and thats no good either..

did you torque them in the right sequence? and to correct spec?

AdderMk2

actually, its good practice to NOT use the end pieces at all.. RTV FTW. thats all I use to seal my lifter valleys

Sidewayz6.0

^^^ What he said. Throw those rail gaskets away. Just use about a 1/4 inch bead of RTV Ultra Black.